To make the update manually you will need to add in the where clause which looks like this in SQL:
SELECT * FROM theTable, usersTable
WHERE usersTable.userID = yourUserIDVariable
So you would need to do this for your query, add in the where clause, set the column you are comparing to, then specify the variable value to compare to.
On your login page you will have the authenticate user server behavior. In here you will see the session variables that are set when the user logs in. Check the one that holds the userID and not the name of the session variable.
When you go back into your query code on the page you can add in the where clause and the reference to the session variable. There are a few ways to do this but the easiest is to concatenate the variable into the query string like this:
".......WHERE usersTable.userID = " . $_SESSION['userID']
In Dreamweaver it is usually done by creating a query variable and assigning the value of your session variable to this query var. Then the query itself is set in an sprintf statement, this function takes a string that references wild card values as %s then it takes the values for these wild cards as the other parameters. Here is a link to the php page on the function: